1. Field of the Invention
This invention relates to the art of seismographic measuring devices, and more particularly concerns apparatus for measuring the intensity of a seismic shock, such as a shock produced by an earthquake.
2. Description of the Prior Art
It is very difficult to precisely determine the intensity of a seismic shock because it is dependent on so many various factors. That is, seismic intensity is dependent on such factors as amplitude, frequency, acceleration, time, wavelength, wave shape, phase, wave envelope, vibration direction, transient phenomena and resonance, and thus, it is impossible to express seismic shock intensity in terms of a single physical quantity. Heretofore, there has been no reliable mechanical apparatus for indicating precisely on a graduated scale the intensity of a seismic shock, taking into account all or most of the important factors heretofore mentioned.